| 摘要 |
PURPOSE:To improve the picture quality with high uniformity for a VTR device by preventing the flaws produced on the outer circumferential surface of an upper cylinder, keeping high accuracy at the repetitive stop positions of the upper cylindr and furthermore attaining automatic operations of a positioning device. CONSTITUTION:When an upper cylinder 1 is fixed on the upper surface side of a rotor 33, a mobile block 57 is moved down by the tip part of a piston rod 58a of a cylinder 58 for the block 57. Thus a reference shaft 60c of a con trol tool 60 supported rotatably by the block 57 and also connected to a pulse motor 59 passes through a control hole 13 of the cylinder 1 and has a contact with the rear end face of a head base 3. The motor 59 is driven while a position shift is read at the tip of a head chip 2 through a TV camera 62. Then the shaft 60c is rotated for control of said position shift. Thus the cylinder 1 is always positioned at a fixed point by means of an upper-stage V block 47 and therefore both the center of the fixed camera 62 and the tip part of the chip 2 can be set approximately at a fixed position respectively. As a result, the position of the tip of the chip 2 can be controlled with high precision.
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